I hear here and there about long term compatability with third party lenses - Mr KR for instance.......Has anyone had long term compatability problems, ie failing to work properly with newly released models etc. Does Canon try to cripple existing third party lenses when introducing a new camera ?

Many reviewers get the lenses far in advance for the purpose of testing it and preparing their reviews, but due to legal restraints are forced to hold off on publishing the reviews until the lens is officially released.